Function of Core C: The primary function of Core C will be to generate, screen, and provide the investigators with genetically altered strains of mice that can be utilized as murine models for influenza infection. To accomplish this goal the core will: (a) coordinate the breeding and weaning of inbred mouse strains required by the individual projects, (b) genetically type the mice utilized in the murine models of influenza, (c) produce new inbred strains of mice required for individual projects, (d) produce and characterize the influenza viral stocks, and (e) generate survival curves for these viral stocks in the mouse strains utilized by the individual projects. This resource will be heavily utilized by Project 1 "The role of CD8 T cells in Lung Immunity", Project 2 "CD4 T cell protection and pathology in the lung", Project 3 "CD8+ T cell memory to respiratory virus infections" and Project 4 "T cell responses of nasal mucosa and lymphoid tissues". The core unit leader is Dr. Frances Lund who is an Assistant Member at the Trudeau Institute and currently is the Scientific Director of the Trudeau Animal facilities. The Trudeau Institute is well known for its expertise in animal models of infectious disease and for its excellent mouse breeding facility. The mouse breeding facility at the Trudeau Institute has all of the resources required to produce the animals required for this Program Project as it currently breeds over 130 different strains of mice including a large number of T cell receptor transgenic, cytokine deficient, and other genetically altered knockout (KO) strains of mice. Approximately half of the strains of mice bred at the Trudeau Institute must be genetically typed and Dr. Lund's lab currently performs the genotypic screening of many of these strains. Additionally, Dr. Lund's lab also performs screening for a number of the ongoing genetic backcrossing projects at the Institute. Thus, Dr. Lund's laboratory has the expertise and the experience required to fulfill the function of Core C.